a hotplate assay, the 118GG homozygous mice displayed a diminished response for up to 3 hours when compared to 118AA mice. These behavioral assays strongly support our electrophysiological observations which suggest that the mutant MOR exhibits an altered morphine pharmacological profile. These results are in agreement with several clinical studies which have shown that carriers of the mutant allele require an increase of the dosing requirements to achieve analgesia or adequate pain control2-3,29.
